Generalized Slotted MAC Protocol Exploiting LoRa Signal Collisions

LoRa is becoming widely used in low-power wide area networks as it enables a communication range of several kilometers with low energy consumption, but with a low bitrate. Collisions in LoRa further reduce the overall performance of the network, and more specifically the throughput. In this paper, we propose a slotted MAC protocol that enables the decoding of colliding LoRa signals. It is based on a new decoding technique at the physical layer that is able to decode the symbols of many frames in collision. Simulation results show that our MAC protocol significantly increases the achievable performance of LoRa networks. For instance, for 25 nodes having a duty-cycle of 10% and with SF7, the throughput with our protocol is 11% larger than the existing protocols.